#include "bits/stdc++.h"

using namespace std;

using ll = long long;
using ull = unsigned long long;

#define IOS ios::sync_with_stdio(0);cin.tie(0);
#define endl "\n"
#define yes cout<<"Yes"<<endl;
#define no cout<<"No"<<endl;
#define rep(i, a, b) for(int i=(a);i<(b);++i)

#define int ll

void solve() {
    int n;
    cin >> n;
    bool is_pos = true, is_neg = true;
    int sabs = 0, minx = numeric_limits<int>::max(), maxx = numeric_limits<int>::min();
    rep(i, 0, n) {
        int x;
        cin >> x;
        is_pos &= x > 0;
        is_neg &= x < 0;
        sabs += abs(x);
        minx = min(minx, x);
        maxx = max(maxx, x);
    }
    if (is_neg) {
        cout << sabs + 2 * maxx << endl;
    } else if (is_pos) {
        cout << sabs - 2 * minx << endl;
    } else {
        cout << sabs << endl;
    }
}


signed main() {
    IOS
    int t;
    cin >> t;
//    t = 1;
    while (t--)solve();
}